Vacuum system



W. J. BARTO VACUUM SYSTEM 2 Sheets-Sheet '1 Filed Nov. 19, 1962 L. W Hmm 5 W w mu 5 mm 5 W H u|l a 1. w

INVENTOR MLL/HNJ 5 4070 W/ 4 TTOR/Vfy W. J- BARTO VACUUM SYSTEM June 8,1965 2 Sheets-Sheet Filed NOV. 19, 1962 INVENTOR. Mum/1d fi/JETO BY ATT'ORNEY Em ll 1 To OTHER Cur-s United States Patent F 3,1875%? VALUUMSYSTEM William 5. Earth, Philadelphia, Pa, assigaer, by mesneassignments, to Yale & Towns, Inc, New Yorh, N.Y., a company of flhioFiled Nov. 19, 1962, Ser. No. 238,451 9 (Claims. (til. 239-1) Thisinvention relates to a vacuum system for vacuum devices, such as vacuumcup load grippers, cement drying devices, vacuum cleaners, or the like.

The invention provides an eflicient, dependable, low cost method andapparatus for continuously supplying a large flow of air for creatingvacuum or suction for such devices, without the use of a separate vacuumor suction pump for this purpose.

This is accomplished in accordance with the invention by providing aninternal combustion engine which will operate efficiently at aparticular sub-atmospheric air pressure; connecting the vacuumattachment to the air intake of the engine whereby the large how of tothe engine for operating the engine may be utilized to create vacuum orsuction for the attachment; and maintaining the air pressure between theengine and the'vacuum operated attachment substantially at saidsub-atmospheric pressure to prevent stalling of the engine. In thismanner, vacuum or suction for the vacuum attachment is provided, withoutthe necessity of a separate pump for this purpose.

Other advantages of the invention will become apparent from thefollowing description and accompanying drawing, wherein: i

FIG. 1 is a side elevational View of an industrial truck incorporating avacuum system constructed in accordance with the invention for providingvacuum for vacuum cups of a load grippingattachment; and

FIG. 2 is a schematic view of the vacuum system illustrated in FIG. 1,showing one vacuum cup gripping the load. 7

Referring to the drawings and in particular to FIG. 1, a vacuum systemconstructed in accordance with the invention is shown applied to aconventional lift truck 10 for the purpose of providing vacuum orsuction for a vacuum cup type load gripping attachment 11. While theinvention is described hereafter with reference to such an attachment,it will be appreciated that the invention may be utilized for othertypes of vacuum attach ments or accessories, such as vacuum cleaners,cement drying attachments, etc. t

The lift truck It) is of conventional construction and includesstationary or primary uprights 12 which are,

mounted on the truck frame, secondary uprights 13 which are mounted forvertical movement on the primary uprights 12, and a load carriage 14which is mounted for vertical movement on the secondary uprights 13. Thevacuum cup load gripping attachment 11 is mounted on the load carriageid, so that a load gripped by the attachment may be raised and lowered.

The particular attachment 11 illustrated in the drawings is of thegeneral type shown in United States Patent No. 2,942,745, and includes aplurality of vacuum cups 15 i for gripping a load. As best shown in FIG.2, each cup 15 is connected to a common manifold 16 through a normallyclosed valve 17. The valve 17 is opened to connect the cup 15 to themanifold 16 through movement of a sensing lever 18 by contact of theouter end of the lever with the load as the cup 15 is moved against theload. By this arrangemeng only those cups which actually engage the loadare connected to the source of vacuum. As also shown in FIG. 2, themanifold 16 is provided with a solenoid operatedvaive 15 which may be3,?87339 Fatented June 8, 1965 actuated to connect the manifold 16 withatmospheric air pressure to simultaneously release the vacuum on all thecups 15 to release the load gripped by the cups.

In handling a load L, truck ill is maneuvered to bring the vacuum cups15 in contact with the surface of the load. As each cup 15 contacts theload, the sensing lever 18 associated with each cup is pivoted throughcontact with the load to open the valve 17 to connect the cup with thesource of vacuum through the manifold 16 so that the vacuum cup gripsthe load. The load carriage 14 then may be elevated to lift the grippedload from the floor to permit the load to be transported by operation ofthe truck. The load may be released by relieving the vacuum on thevacuum cup 15 by actuation of the solenoid operated valve 19.

In accordance with the invention, vacuum is provided for the attachment11 by providing an internal combustion engine which will operateefficiently at sub-atmospheric pressure, e.g., at 16 inches of Hg;connecting the air intake of the engine with the vacuum attachmentwhereby the large volume of air which is drawn through the air intake ofthe engine during operation of the engine may be utilized to createvacuum or suction for the attachment; and maintaining the air pressurebetween the air intake and the attachment substantially at saidsubatmospheric pressure, to prevent stalling of the engine due to airstarvation or excessive air.

In the drawings, the internal combustion engine is 7 shown at 2.6suitably mounted on a convenient part of the truck ill. The engine 20 isof conventional construction and, as best shown in FIG. 2, includes aconventional carburetor 21 having an air intake 22, an injection nozzle23 through which fuel is injected into the carburetor and mixed with airentering the carburetor through the air intake 22, and a needle valve 24which is adjusted so that the flow of fuel to the carburetor is suchthat the engine will operate at the sub-atmospheric air pressure.

The air intake 22 of the carburetor 21 is connected to the manifold 16of the attachment 11 by means of a pipe 25 and flexible hoses 26 and 27,so that the large volume of air drawn through the air intake 22 of thecarburetor 21 for operating the engine is available for creating vacuumor suction for the vacuum cup attachment 11. As shown in FIG. 1, thehose 27 may be reeved around a Weighted, sliding reel 28, so that slackin the hose 27 is taken up asthe attachment 11 is raised and loweredwith the carriage 14.

The air pressure between the air intake 22 and the manifold 15 ofattachment 11 is maintained substantially at the sub-atmosphericpressure to which the engine 243 is adjusted by means of a bypass valve29 and a metering valve 3r).

The bypass valve 29 is connected to the pipe 25 and admits air to theair intake 22 to prevent stalling of the engine 20 by air starvation inthe event that all the vacuum cups 15 are closed off by the valves 17 orare covered by the surface of a non-porous load.

The metering valve 30 is connected between the end of the hose 27 andthe manifold 16 and meters the air from the attachment 11 to the airintake 22 to prevent excessive flow of air to the carburetor andstalling of the engine 29 in the event that the vacuum cups 15 are notin full contact with the load, or the load is of such porosity as toallowexcessive flow of air through the cups. By positioning the meteringvalve 39 between the hose 27 and the manifold 16, the long lengths ofhoses 26 and 27 serve as a vacuum storage. A vacuum storage tank can,

of course, be connected in the line between valve 29 and valve 3t ifdesired.

As best shown in FIG. 2, the bypass 'valve 29 is a simple pressureoperated valve and includes a valve member 3 1 which is normally heldclosed by a spring 32 to pre vent the flow of air at atmosphericpressure through the valve to the pipe 25 and air intake 22 of thecarburetor 21. It the pressure between the air intake 22 and themanifold :16 of the attachment 11 decreases below that to which theengine is adjusted, the valve member 31 opens against the pressure ofthe spring 32 to admit air to the air intake 22 to prevent stalling ofthe engine by air starvation. The force exerted by the spring 32 and,therefore, the pressure diiferential at which the valve member 31 opens,may be adjusted by a screw 33.

p The metering valve 36 includes a piston 34, normally held in theposition shown in FIG. 2, by a spring 35. In this position of the piston34, air maypass from the manifold 16 through small ports 36 in aperipheral flange of the piston, through slots 37 in the inner end ofthe piston into a chamber 38 of the valve, and to the hose 27, tomaintain the vacuum or suction on thecups. If the cups are onlypartially covered by the load, or the load is of high porosity, so thatthere is a large flow of air from the cups, the high rush of air throughthe ports 36 creates a pressure difierential between the outer end ofthe piston 34 and the inner chamber 38, causing the piston 34 tornoveinwardly of the valve against the pressure of the spring 35 until theinner surface 39 of the peripheral flange of the piston 34 engages aseat 46 in the valve body to close off flow of air through the ports 36.In this manner, an excessive flow of air to the 'air intake 22 of thecarburetor 21, which would otherwise cause stalling of the engine, isprevented. During this inward movement of the piston 34, air is trappedin a chamber 41 in the valve body by a reduced portion 34a of the piston34 to provide a dashpot effect which slows down or causes slight timedelay in the inward movement of the piston 34 to allow time forbalancing of the air-fuel mixture in the carburetor. A small opening 42in the end of the piston 34 permits the piston to return to its originalposition when the flow of air from the cups decreases to that requiredfor operation of the engine. The pressure exerted by the spring 35 and,therefore, the pressure differential at which the valve operates may beadjusted by means of an adjusting screw 43.

Fromthe preceding description, it can be seen that by continuousoperation of the internal combustion'engine 20, a large fiow of air atsub-atmospheric pressure is available for creating vacuum or suction foroperation of the attachment 11, without providing a separate vacuum orsuction pump for this purpose. Adjustment of thecarburetor 21 of theengine 2% during operation of the engine, to prevent-stalling of theengine as the demands of the vacuum attachment '11 for air varies, isnot necessary, as the valves 29, 30 maintain the air to the carburetor21 at substantially the pressure to which the engine is ad justed tooperate elfectively. Thus, a very dependable source of vacuum or suctionis provided for operating the attachment.

While one embodiment of the inventionhas beet 1 shown and described, itwill be appreciated that this is for the purpose of illustration andthat changes and modifications may be made therein without departingfrom the spirit and scope of the invention.

I claim:

1. The method of supplying air at sub-atmospheric pressure to a vacuumdevice by means of an internal combustion engine operable at aparticular sub-atmospheric pressure comprising,

connecting the vacuum device with the air intake of said internalcombustion engine whereby the large volume of air drawn through saidairintake may be utilized to create vacuum for said vacuum device,

operating the engine whereby a large volume of air is drawn through theair intake of the engine, and automatically maintaining the air pressurebetween the vacuum device and the air intake of said engine subdstantially at said particular sub-atmospheric air pressure to preventstalling of the engine.

2. In a combination of the class described,

an internal combustion engine,

a vacuum device,

conduit means connecting said vacuum device with said internalcombustion engine whereby air supplied to said internal combustionengine to support combustion in said engine flows from said vacuumdevice, and

a pressure responsive bypass valve operable by a predetenmined decreasein the pressure in said conduit means to supply air to said internalcombustion engine when insufiicient air is supplied through said vacuumdevice whereby to prevent stalling of said internal combustion engine.

3. In a combination of the class described,

an internal combustion engine, W

a vacuum device,

conduit means connecting said Vacuum device with said internalcombustion engine whereby air supplied to said internal combustionengine to support combustion in said engine flows from said vacuumdevice, and

pressure responsive valve means operable by a predetermined increase inthe air pressure in said conduit means to prevent excessive flow of airto said engine from said vacuum device whereby to prevent stalling ofsaid engine.

4. In a combination of the class described,

an internal combustion engine,

a vacuum device,

conduit means connecting said vacuumdevice with said internal combustionengine whereby air supplied to said internal combustion engine tosupport combustion in said engine flows from said vacuum device, and v apressure responsive bypass valve operable by a predetermined decrease inthe presence in said conduit means to supply air to said internalcombustion engine when insulficient air is supplied through said vacuumdevice whereby to prevent stalling of said internal combustion engine,and

further pressure responsive valve means operable by a predeterminedincrease in the air pressure in said conduit means to prevent excessiveflow of air to said engine from said vacuum device whereby to preventstalling 0t said engine.

5. In a combination of the class described,

an internal combustion engine operable at a particular sub-atmosphericair pressure,

a vacuum device,

conduit means connecting the air intake of said engine with said vacuumdevice whereby the large volume of air drawn through said air intake foroperating said engine may be utilizedto create vacuum for said vacuumdevice, and

pressure responsive valve means operable by air pressure within saidconduit means to maintain the air pressure within said conduit meanssubstantially at said particular sub-atmospheric pressure whereby toprevent stalling of said engine.

6. In a combination of the class described,

an internal combustion engine operable at a particular sub-atmosphericair pressure,

a vacuum device, a

conduit means connecting the air intake of said engine with said vacuumdevice whereby the large volume of air drawn through said air intake foroperating said engine may be utilized to create vacuum for said vacuumdevice, and

a pressure responsive bypass valve operable by a pre- I air from saidvacuum device is insuflicient to support operation of said engine.

7. In a combination of the class described,

an internal combustion engine operable at a particular sub-atmosphericair pressure,

a vacuum device,

conduit means connecting the air intake of said engine with said vacuumdevice whereby the large volume of air drawn through said air intake foroperating said engine may be utilized to create vacuum for said vacuumdevice, and

pressure responsive metering valve means operable by a predeterminedincrease in the air pressure in said conduit means above said particularsub-atmospheric air pressure to prevent excessive flow of air from saidvacuum device to said engine whereby to pre- 'vent stalling of saidengine.

8. In a combination of the class described,

an internal combustion engine operable at a particular sub-atmosphericair pressure,

a va'cuum device,

conduit means connecting said vacuum device with said internalcombustion engine whereby air drawn through said conduit means tosupport combustion in said engine may be utilized to create vacuum forsaid vacuum device,

a pressure responsive bypass valve operable by predetermined decrease inthe air pressure in said conduit means below said particularsub-atmospheric air pressure to supply air to said internal combustionengine when insuflicient air is supplied through said vacuum device tosupport operation of said internal combustion engine, and

pressure responsive metering valve means operable by a predeterminedincrease in the air pressure in said conduit means above said particularsub-atmospheric air pressure to prevent excessive flow of air from saidvacuum device to said engine whereby to prevent stalling of said engine.

9. The method of supplying air at sub-atmospheric pressure to a vacuumdevice by means of an internal combustion engine operable at aparticular sub-atmospheric pressure at the canburetor comprising thesteps of,

References Cited by the Examiner UNITED STATES PATENTS 974,286 11/ 10Matchette et a1 60-60 2,5 05 ,292 4/5 0 Mallory 606O 2,893,581 7/59Cushman 214-651 2,942,745 6/60 Horton 2 14-650 3,110,517 11/63 Olson eta1. 214651 X JULIUS E. WEST, Primary Examiner.

EDGAR W. GEOGHEGAN, Examiner.

1. THE METHOD OF SUPPLYING AIR AT SUB-ATMOSPHERIC PRESSURE TO A VACUUMDEVICE BY MEANS OF AN INTERNAL COMBUSTION ENGINE OPERABLE AT APARTICULAR SUB-ATMOSPHERIC PRESSURE COMPRISING, CONNECTING THE VACUUMDEVICE WITH THE AIR INTAKE OF SAID INTERNAL COMBUSTION ENGINE WHEREBYTHE LARGE VOLUME OF AIR DRAWN THROUGH SAID AIR INTAKE MAY BE UTILIZED TOCREATE VACUUM FOR SAID VACUUM DEVICE, OPERATING THE ENGINE WHEREBY ALARGE VOLUME FOR AIR IS DRAWN THROUGH THE AIR INTAKE OF THE ENGINE, AND